Quantum Trajectories
Mostrando 1-12 de 12 artigos, teses e dissertações.
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1. Geometria e simetrias do emaranhamento
In the present work we present a geometric method to identify and measure the degree of entanglement of a two-qubit state. It is based on writing a map of the system state, from a non-unitary transformation. By introducing new parameters for such 4X4 matrix, the product of eigenvalues, two by two, acquire the form of squared 4D distances, having a Minkowski
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 20/05/2011
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2. Extended Bell´s Be-ables and Atenuattion × Amplification Competition. / Extensão dos Be-ables de Bell e Competição Atenuação x Amplificação
In the first part of this work we employ the Itô stochastic equation to extend Bells be-able interpretation of quantum mechanics to encompass dissipation, decoherence and quantum-to-classical transition through quantum trajectories. For a particular choice of the source of stochasticity, the one leading to a dissipative Lindblad type correction to the Hamil
Publicado em: 2009
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3. Integrals in the coherent state representation / Integrais de trajetoria na representação de estados coerentes
The overcompleteness of the coherent states basis gives rise to a multiplicity of representations of Feynman?s path integral. These different representations, although equivalent quantum mechanically, lead to different semiclassical limits. Baranger et al derived the semiclassical limit of two path integral forms suggested by Klauder and Skagerstam. Each of
Publicado em: 2008
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4. Quantum baker maps for spiraling chaotic motion
We define a coupling of two baker maps through a pi/2 rotation both in position and in momentum. The classical trajectories thus exhibit spiraling, or loxodromic motion, which is only possible for conservative maps of at least two degrees of freedom. This loxodromic baker map is still hyperbolic, that is, fully chaotic. Quantization of this map follows on si
Brazilian Journal of Physics. Publicado em: 2007-06
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5. Interactions of physical systems with applications in quantum optics and quantum information / Interações de sistemas fisicos com aplicações em optica e informação quantica
A presente tese é dedicada à utilização de conhecidos sistemas quânticos em aplicações de interesse em óptica e informação quântica. Motivados pelos recentes avanços experimentais em sistemas formados por íons aprisionados interagindo com lasers e na eletrodinâmica quântica de cavidades, nós focamos grande parte de nossas propostas nestes sis
Publicado em: 2006
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6. Classical trajectories and quantum field theory
The density matrix and the Wigner function formalism requires the doubling of the degrees of freedom in quantum mechanics (QM) and quantum field theory (QFT). The doubled degrees of freedom play the role of the thermal bath or environment degrees of freedom and are entangled with the system degrees of freedom. They also account for quantum noise in the fluct
Brazilian Journal of Physics. Publicado em: 2005-06
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7. A new form of path integral for the coherent states representation and its semiclassical limit
The overcompleteness of the coherent states basis leads to a multiplicity of representations of Feynman's path integral. These different representations, although equivalent quantum mechanically, lead to different semiclassical limits. Two such semiclassical formulas were derived in [1] for the two corresponding path integral forms suggested by Klauder and S
Brazilian Journal of Physics. Publicado em: 2005-03
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8. Estudos semiclassicos na representação de estados coerentes
In this work we develop and apply a semiclassical approximation to the coherent-state propagator K(z",z ,t) = (z"iHt/h)z ), where H is the Hamilton operator for the suystem and z) represents the coherent states of the harmonic oscilator. The semiclassical K(z",z ,t) makes use of a stationary phase approxiamtion in which stationary trajectories inhabit is stu
Publicado em: 1997
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9. Random Walk of Processive, Quantum Dot-Labeled Myosin Va Molecules within the Actin Cortex of COS-7 Cells
Myosin Va (myoVa) is an actin-based intracellular cargo transporter. In vitro experiments have established that a single myoVa moves processively along actin tracks, but less is known about how this motor operates within cells. Here we track the movement of a quantum dot (Qdot)-labeled myoVa HMM in COS-7 cells using total internal reflectance fluorescence m
The Biophysical Society.
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10. Nonequilibrium entropy, Lyapounov variables, and ergodic properties of classical systems
We discuss the problem of defining (nonequilibrium) entropy in terms of the concepts of mechanics and of reconciling its monotonic increase with the Hamiltonian evolution of the dynamical system. This leads to investigating necessary and sufficient conditions for the existence of monotonically increasing quantities or the so-called Lyapounov variables of cla
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11. Molecular dynamics simulation of photodissociation of carbon monoxide from hemoglobin.
A molecular dynamics simulation of the photodissociation of carbon monoxide from the alpha subunit of hemoglobin is described. To initiate photodissociation, trajectories of the liganded molecule were interrupted, the iron-carbon monoxide bond was broken, and the parameters of the iron-nitrogen bonds were simultaneously altered to produce a deoxyheme conform
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12. Structure and dynamics of a proton wire: a theoretical study of H+ translocation along the single-file water chain in the gramicidin A channel.
The rapid translocation of H+ along a chain of hydrogen-bonded water molecules, or proton wire, is thought to be an important mechanism for proton permeation through transmembrane channels. Computer simulations are used to study the properties of the proton wire formed by the single-file waters in the gramicidin A channel. The model includes the polypeptidic